Throttle arrangement for pneumatic tools



Sept.. l?, 1935. E. W. STEVENS v n THROTTL ARRANGEMENT FOR PNEUMATIC TOOLS Filed Jan. 25, 193s lNvENToR Eon/ARD ,//K STEVE/vs,

ATTORNEY EWBW/ Patented Sept. 17, 1935 PATENT OFFICE THROTTLE ARRANGEMENT FOR PNEUMATIC TOOLS Edward W. Stevens, Detroit, Mich., assignor. to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application January 25, 1933, Serial No. 653,405

3 Claims.

This invention relates to fluid actuated tools and more particularly to a throttle operating mechanism which may be manipulated by an operator without interfering with his grasp on the tool handle. The application of the invention is especially suited for tools of the type which have acontrol valve located in the backhead in line with and forward of the grip portion of the tool handle.

An object of the invention is to provide a throttle lever associated with a radially extending tool handle, and adapted to be grasped together with the latter. Another object is to arrange such a throttle lever that it may actuate `a valve stem below the tool handle and in line with the radius of the tool. It is old to use a valve lever to operate a throttle valve disposed within a hollow cross handle, but the presence of the valve in the handle interferes with the removability of the latter. It has been proposed to set the throttle Valve below the cross handle and to place the valve on one side of the axis of the tool so. that the lever could be mounted upon the corresponding side of the tool handle. Such an arrangement has several disadvantages-e. g.: the air supply inlet is off-center and out of` balance, the lever extension is weak and subject to damage, and the symmetry of design is destroyed. These disadvantages are overcome by the vpresent invention.

A further object of the invention is to provide a combination of handle grip members and throttle lever, each of which is removable independently of the other or others. In accordance with this object, the throttle lever is so constructed that it may be slipped'over the free endV of one of the handle grip portions and readily secured to the back-head. v-

A feature of the invention resides in the fact that the throttle lever is in one piece and capable of being manufactured at a low cost. Other objects and features of the'invention will appear more clearly from the following description taken in connectionv with the accompanying drawing and appended claims.

In the drawing, which represents one illustrative embodiment of the invention:

Fig. 1 is a sectional View of the invention;

Fig. la is a continuation of the lower end of Fig. 1;

Fig. 2 is a plan View;

Fig. Bis a fragmentary side View, looking from right to left in Fig. 1, and showing the back-head,`

throttle lever and associated'parts; Fig. 4 is an elevational View of a blank from which theV valve lever is formed; and

Fig. 5 is a side View looking from the left in Fig. 4.

Referring to Fig. 1, the cylinder III is shown as provided with the conventional front-head II,

hammer piston I2, and working tool I3, which is illustrated in the form of a coal pick. Intermediate the ends of the cylinder is an exhaust consisting of'ports I4. The rear end of the cylinder is fitted, as by screw threads l5, into the back-head It. The cylinder and back-headare locked tightly to each other by means of the bolt Il passing through ears I8 on the back-head. Interposed between the rear end of the cylinder and the back-head is; a distributing valve case comprising thesections and 2l. The forward section 2-I is recessed to receive the annular distributing valve 22 and is provided Vwith passages 23 leading from the forward face of the valve to `the rear end ofthe piston chamber.

The rearward section or lid 20 of the distributing` valve case is provided with ports 24 leading from the rear face of the valve through the annular passage 25 and the longitudinal passage 26 -to the front end of the piston chamber. The valve 22 and lid 20 of the valve case are both provided with a central bore communicating by means of the bore 2l in the back-head with a manually controlled source of motive uid to be described presently.

The 'operation of the Vparts so far described is as follows: The valve 22 is reciprocable axially and normally rests against either one of the section 2D or 2| of the valve case, depending upon the predominance of fluid pressure upon the opposite radial faces of the valve. In the position shown in Fig. 1, the valve is resting on its forward or lower seat, being held by live air on one side and having its other side communicating with atmosphere through the exhaust I 4. Live air is conducted through the ports 24 and passages 25 and 26 to the forward end of the piston chamber, thereby forcing the piston rearwardly. After the head of the piston has passed the exhaust I4, the pressure fluid in the forward part of the piston chamber is vented and, consequently pressure on the rear face of the valve 22 is reduced.' At the same time, the air inthe rearward end of the piston chamber, which communicates with the forward face of the valve, isy compressed by the piston and trips the valve to its rearward position. As a result, live air is admitted through the central bore in the valve and passes underneath the surface of the latter and through the ports 23 to the rear end of the piston chamber. 'I'heair thus admitted forces the piston forwardly until the latter has passed the exhaust I4 when the valve is tripped back to the Fig. 1 position.

The air admitted through the port 21 to the distributing Valve 22 is-psubject tothe control of a throttle valve 29 mounted in a radial bore 3l) in the back-head. This valve is arranged to reciprocate in a line which is radial with respect to the axis of the cylinder. In its normal or inoperative position, the head of the throttle valve is yieldingly held against its seat 3|, by means of a` spring 32 interposed between the valve and a hollow goose neck 33. The goose neck provides a means of attachment to an air supply hose (not shown) and is swivelly secured in the back-head by means of a plug 34 threaded into a counterbore in the bore 38. Alined with the bore is a reduced extension or bore 36 which slidably receives the valve stem 31. This stem projects through the outside surface of Ythe back-head to cooperate with the throttle lever 38, the construc- 4tion of which will be described subsequently.

To provide means for manually supporting the tool, lthe back-headl is constructed with two upstanding arms 40, 4| to which is attached a suitable handle arrangement. These arms have alined perforations 43 which receive the clamping bolt 44. This bolt is surrounded by a series of rubber covered sleeves 45 which form the grip members of the handle.

The throttle lever 38 is pivotally mounted upon a pin 46 passing through a bore in the arm 4|. rI'he lever has two parallel vertical arms 48 and 49 engaging opposite sides of the arm 4I on the back-head. At their upper ends the arms 48 and 49 terminate inV a substanially horizontal manipulative portion 50 which, when the lever is rocked about the pin 46, may overlie one of the grip sleeves 45. The manipulative portion may be grasped by the operator together with the grip sleeve, and is preferably arcuate in cross-section to conform to the shape of the latter. Connect- `ing the two vertical arms 48 and 49 at their lower and 5.

ends and integral therewith, is a bridge or crossmember 5l which is provided with a central depending tongue 52 engaging the outer end of the valve stem 31. In order to protect this tongue, a flange 53 partially surrounding the same is provided on the back-head. Y

The valve lever 38 is preferably formed from sheet metal although it could be made from a forging. The blank form is illustrated in Figs. 4 The side arms are bent backward (see Fig. 4) from the plane of the cross-member 5| along the lines X-X. The manipulative or handle`portion 50 will then be facing the observer and in the same vertical plane as the arm 48. The

-manipulative portion is then curved until the surfaces Y-Y abut each other. When the blank has thus been folded into shape the end surfaces Y-Y are joined by welding.

To assemble the valve lever 38 on the handle of the portable tool it is merely necessary to slip` the valve lever over the end of one of the handle grip members, and insert the pin 46 through alined apertures in the arm 4| and valve lever respectively. The valve lever normally is held in the Fig. 1 position by the pressure of spring 32 acting through the valve stem 3".Y Downward pressure on the manipulative portion 50, however, rocks the valve lever, forces back the spring and opens the throttle valve as will be understood by those skilled in the art.

changes, modifications and adaptations within the scope of the appended claims.

I claim as my invention:

1. A fluid pressure tool comprising a cylinder, a back-head at the upper end thereof, a handle supporting arm projecting upwardly from said backhead, a radially extending grip handle supported at the upper end of said arm, a valve in said backhead, said valve being reciprocable along a line radial with respect to the cylinder axis and parallel to the grip handle, and means for actuating said valve, said means comprising a valve lever having a side arm pivotally connected to the handle supporting arm and adapted to rock about an axis located between the valve and the grip handle and transverse to the latter, the upper end of the side arm being rigidly connected to a manipulative portion and the lower end rigidly connected to a cross-arm operatively connected to the valve, the manipulative portion being above the grip handle and overlying the latter, said side arm being ollset from a radial plane which includes the valve and the manipulative portion of the lever, said lever being removable in a radial direction from the grip handle and handle supporting arm while the two last-mentioned elements are connected to each other.

2. A fluid pressure tool comprising a cylinder, a

back-head at the upper end thereof, a handle supporting arm projecting upwardly from said backhead, a radially extending grip handle supported at the upper end of said arm, a valve in said backhead, said valve being reciprocable along a line radial with respect to the cylinder axis and parallel to the grip handle, and means for actuating said valve, said means comprising a valve lever having two parallel side arms pivotally connected on opposite sides of the handle supporting arm and adapted to rock about an axis located between the valve and the grip handle and transverse to the latter, the side arms being connected at their upper end by a manipulative portion and at their lower end by a cross-arm operatively connected to the valve, the manipulative portion being above the grip handle and overlying the latter, said side arms, cross-arm and manipulative portion forming a substantially closed loop encompassing the grip handle and handle supporting arm and being removable radially from said handle and supporting arm while the two last-mentioned elements are connected to each other.

3. A uid pressure tool comprising a cylinder, a. back-head at the upper end thereof, a pair of handle supporting arms projecting upwardly from said back-head, the upper ends of said arms being perforated to receive a radially extending rod, sleeves on said rod providing grip members, a valve in said back-head and a lever for operating said valve, said lever comprising two parallel side arms connected at their upper end by a manipulative portion and at their lower end by a cross piece, said parallel arms being suiiiciently spaced apart to receive therebetween one of the handle supporting arms and one of the handle grip members, said parallel arms having pivotal engagement with the opposite sides of said one handle arm and adapted to swing about an axis located between the valve and the rod and transverse to the latter, the manipulative portion of the lever lying above one of the grip members, and the cross arm having a portion movable radially and operatively connected with the valve. 

